Location finder



Dec. 15, 1936. o. A. BOCH LOCATION FINDER Filed May 10, 1935 5 Sheets-Sheet 1 7'0 RL'C'll Ek INPUT INVENTOR ATTORNEY Dec. 15, 1936. Q BQCH 4 2,063,906

LOCATION FINDER Filed May 10, 1955 5 Sheets-Sheet 2 INVENTOR X ATTORNEY 15,-1 936. Q A C 2,063,906

LOGATION'FINDER 5 ATTORNEY Dec. 15, 1936. o. A. BOCH LOCATION FINDER FiledMay 10, 1935 5 Sheets-Sheet 4 INVENTOR 05042 ,4 600/ W M U ATTORNEY Dec. 15, 1936. Q BOCH 2,063,906

LOCATION FINDER Filed May 10, 1935 5 Sheets-Sheet 5 4 0 M 6 7 w m,

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INVENTOR ATTORNEY Patented Dec. 15,1936

PATENT OFFICE LOCATION FINDER Oscar A. Book, Brooklyn, N. Y., assignor of onehalt to William V. Hagendorn, Kew Gardens.

Application May 10, 1935, Serial No. 20,729

16 Claim.

This invention relates to location finders in general and more particularly to devices which will indicate to the attendant the location of a conveyance, such as an airplane, vessel, automobile or the like.

Among the objects of the present invention, it is aimedto provide a device for locating not only the place relative to the earth over which an airplane may be positioned or the place on the earth-where a vessel, automobile or other conveyance may be positioned but in addition also chart thepath of such conveyance during movement of the same so that the navigator, observer, attendant or the like may at any moment determine the location during movement of the conveyance.

- It is still another object of the present invention to provide an improved location finder cooperating with'a plurality of sources of radio frequency or the like disposed at a plurality of It is son a further object of the present invention to provide an improved location finder for use on a conveyance such as an airplane, vessel, automobile or the like cooperating with the radio impulses having difierentfrequencies' of three predetermined' broadcasting stations whereby indicators will be moved relative to a map to indicate to the observer not only the location of the conveyance at any particular moment but also chart the path of the conveyance during movement.

These and other features, capabilities and advantages of the invention will appear from the detail "description of one specific embodiment thereof illustrated in the accompanying drawings in which- Figure 1 illustrates more or less diagrammatically the several elements of the location finder together with a wiring diagram showing the electrical connections of the several parts;

Fig. 1A shows charts illustrative of the geometrical problem upon which the invention is based;

Fig. 2 is a section on the line 2-2 of Fig. 1; *Fig. 3 is ajsection on the line 3-3 of Fig. 4;

Fig.4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a section on the line 5-5 of Fig. 4'

Fig. 6 is a section on the line H of Fig. 4:

Fig. 7 is a section on the line 1-1 of Fig. 6;

cities on the map I.

Fig. 8 is a fragmental transverse section taken on the line 88 of Fig. 3;

Fig. 9 is a fragmental plan enlarged as compared to Fig. 8 showing one of the resistance devices used;

Fig. 10 is a transverse section still further enlarged as compared to Fig. 9 showing the operative relation of the resistance device to its control means;

Fig. 11 is a section on the line ll--ll of Fig. 10; 10

Fig. 12 is an enlarged side elevation of the part of the apparatus which is positioned on a map shown in the lower part of Fig. 1; and

t Fig. 13 is an enlarged fragmental view of a part of the device shown in Fig. 12. I 15 In the embodiment illustrated. a map I is used on which a portion of the apparatus is positioned relative to three broadcasting stations of different frequencies so that the pins 2, 3 and 6 are pierced into the map I in alinement with go the three broadcasting stations selected. The pins 2 and 4 correspond to the centers of rotation of the needles of the meters 5 and 6 and the pin 3 corresponds with the center of rotation of the axis 7.

In the present instance, the broadcasting sta tions at Cleveland, Washington and New York are selected of diflerent radio frequencies and the pins 2, 3 and 4 pierced into the locations of these Secured to the meters 5 and 6 are the pointers or indicating arms 8 and 9 which will cross one another according to the 'present invention at the point P in alineme'nt with the location on the map I where the conveyance islocated.

'of a radio impulse at right angles to an imaginary line drawn from the source to the plane of the loop aerial.

In the present invention, three such automatically actuated loop aerials are used and are diagrammatically shown in Fig. 1A as I0, H and I2.

If for instance the points A, B and C are selected as the locations of the sources of radio impulses 'and the aerials l0, H and I! are tuned to the frequencies of the stations A, B and C respectively according to this loop antenna radio finder they will position themselves as indicated in Fig. 1A to face the stations A, B and C.

If lines are drawn at right angles to the faces of the loop aerials III, II and 2.toward their respective stations A, B, and C and lines connecting the stations A, B and C relative to the unknown location form a closed triangle outside of the unknown location then the lines A, B' and should intersect at a point coinciding with the unknown location,-it is then only necessary to devise apparatus whereby two indicating arms, such for instance as the "arms 8 and 9 of Fig. -1, will be actuated to correspond with the imaginary lines A and C.

In the present instance, the lines A and C' from their respective aerials l0 and I2 to their respective stations A and C intersect at a point P. It is of course also known that a circle can be described through any three points which we will to intersect the circle D at some point P. If the lines CP' and AP are now drawn. it is of course apparent that the angle a formed between the lines A and B within the circle D is equal to the angle a iormed at the point C between the lines AC and CP' since they intercept the same are AP. It will also appear that the angle b formed at the point P by the lines B and C' will equal the angle 12' formed at the point A between the lines 31A and AP since they intercept the same are From the foregoing, it will also appear that the angle 0 formed at the point P between the lines AP and BP' will equal the angle 0' formed at the point C between the lines AC and PC because they intercept the same are AP and that the angle d formed at the point P between the lines BP'and CP will equal the angle d formed at the point A between the lines PA and CA since they interceptthe same are PC.

From the foregoingQ-it will then appear that if the angles 0 and d canbe' measured and trans-' lated into-mechanical forces that arms extending from the points A'and C in the direction of the point P can be controlled to form the angles 0' and d to intersectatthe'pointP.

"The apparatus now to be described will show how these angles cand d are determined and measured and so translated into mechanical forces in turn to actuate the arms 8 and 9 of Fig. 1 to intersect at the point P.

known point of location to the known points of location'of the sources of radio impulses received; the housing It in which is mounted the mechanism for translating the angles so measured intomechanical forces and the map I and associated instrument supporting the indicating arms 3 and,

9 controlled by the forcesso translated by the mechanism in the housing It a The radio control in the..present instance consists of three radio receiving units, each connected with one of the loop,aerials Ill, II and I2,

and each in turn connected with a meter, such as an indicating arm or needle ll.

The wiring between each loop aerial and its meter M is substantially identical one to the other and therefore only one wiring diagram is illustrated, the wiring diagram for the aerial l0, it being connected by the conductors l8 and 9 to the condenser 2,0 which is operative to tune in the aerial III, the ends of which in turn are connected to the rectifier tubes 2| and 22 through the equal condensers 23 and 24 respectively.

An alternating voltage 01 a frequency readily passed by the audio amplifier (not shown) of the radio receiving unit is applied in opposite phase through the radio frequency inductors 25- and 26 to the plates of the rectifier tubes 2| and 22 respectively. The cathodes of the rectifier tubes 2| and 22 are connected one to each end of the resistor 21, the adjustable center tap of which passes through the audio output transformer 29 of the radio receiver to ground. The meter M is connected across this resistor 21. Condenser 28 is a high capacity, low voltage electrolytic condenser which damps the meter M. An audio oscillator including the,oscillation transfer 29 supplies voltage to the rectifier tubes 2| and 22 across the voltage divider formed by the resistors 30 and 3|. The resistors 30 and 3| of the voltage divider are substantially equal resistors accurately matched to about one-half of one per cent to insure equal voltages of opposite phase for the rectifier tubes 2| and 22. The resistor 32 may be added to the circuit to reduce the efiect of any changes in the resistance tubes 20 and 22. Greater sensitivity however will result if the resistor is omitted.

From the foregoing, it will thus appear that when a positive voltage is applied to the plate of .the rectifier tube 2| by the audio oscillator identified by the transformer 29, a negative voltage is applied to the plate of the rectifier tube 22, whereupon the rectifier tube 2| will draw current and will have low resistance to ground and the rectifier tube 22 will be. cut off with high resistance to ground. When the phase reverses the rectifier tube 2| will be cut oil. and the rectifier tube 22 will draw current and the grounding point of the loop antenna ID will be reversed about its center point, thereby the field pattern of the loop a'ntenna will be rapidly reversed and dissymmetry is obtained by placing the ends of the loop antenna alternately at ground. I

The currents of the rectifier tubes 2| and 22 produced by the voltage or the audio oscillator identified by the transformer 29 pass through the meter M in opposite directions when the voltage of the audio oscillator identified by the transformer 29 is applied equally to these rectifier tubes 2| and 22. The currents will be equal and the. meter will read zero indicating that the aerial I0 is trained at right angles to the source of the radio impulse. Remembering that when the rectifier tube 2| passes current, one loop antenna field pattern will be produced and current passes through the meter M in one direction and when the rectifier tube 22 passes current, another field pattern will be produced and current passes through the meter M in the other direction, the efiect of an incoming radio wave will be obvious. When the loop antenna is grounded at one end, the signal at the output of the radio receiver will be proportional to the field pattern for that condition and the current through the meter M will be proportional to the voltage of the audio oscillator and the output voltage.

When the loop antenna is grounded at the other end similar conditions will hold but there will be a reversal of current in the meter M. Since the currents through the meter M due to the audio oscillator will be equal'and opposite currents defleeting the needle I! right or left are directly proportional to the difference between the output voltages due to each field pattern.

The mechanism now to be described has been devised automatically to set and maintain each aerial at right angles to the direction of the radio impulse. The aerials I 8; and I2 aremounted upon shafts 33, 34 and 35 respectively journaled in the support 36. The shafts 33, 34 and 35 have fixed thereto the pinions 31, 38 and 38 respectively and have also fixed thereto the sprocket wheels 48, 4| and'42 respectively, sprocket wheel 48 being in the present instance disposed at the highest level as indicated in Fig. 1, sprocket wheel 4! disposed at the next lower level and sprocket mvheel 42 at the lowest level.

Thepinions 31, 38 and 38 mesh with'the spur gears 43, 44- and 45 fixed onthe shafts journaled in the support 36 on'which in turn are fixed the beveled gears 46, 41 and 48 respectively in mesh with the beveled gears 48, 58 and on the shafts 52, 53 and 54 of the motors 55; 56 and 5! respectively.

Each of the motors 55, 56 and 51 in turn are connected to the meter M of the radio receiver unit connected to its associated loop aerial. The operative connection between the meter M of the aerial l8 and the motor 55 typical of all of such connections is illustrated and will now be described.

The motor 55 is a reversible motor connected by the conductor 58 with a source of current supply 58, connected by the conductor, 68with one of its, windings for turning the'motor in one direction and connected by the conductor 6! with the other of its windings for turning the motor in the reverse direction. The conductors 68 and 6| terminate in contacts 62 and 63 respectively, each of which to the exclusion of theother is adapted to be engaged by the movable contact 58' connected to the source of current supply 58.

The. movable contact 58' is in turn controlled by the electromagnets 64 and" 65 to be actuated intoengagement with either one or the other of said contacts 62 or 63. Either of the electromagnets 64 or 65 to the exclusion of the other may be to the reflector 6-1 in turn to be directed onto a light sensitive body, such as the selenium cell 68 whereby a current will be established in the conductors connectingthe selenium cell 68 with .the magnet 64 in turn to energize the same and attract the movable contact 58' toward it into engagement with the terminal contact of the conductor 6| thereby to establish the current for the motor'55 and cause it to turn in one direction to return the loop aerial 'l8 'toa direction at right angles to its radio impulse. One terminal of the selenium cell 68 is connectedfby the conductor p 68 with one terminal of the electric magnet 64 while the other terminal is connected by the conductors ,'|8,,|I and 12 with the other terminal of theelectricmagnehflhj t N If, on the other hand, the needle I! is deflected to the right, the light rays from the lamp 66 will be deflected by the deflector 61 onto the selenium cell 13 to energize the electric magnet 65 in turn to attract the movable contact 58' into engagement with the terminal contact of the conductor 68 thereby to establish the circuit for the motor through the conductor 68 to actuate the motor in the reverse direction to that effected when the movable contact 58' engages the terminal contact of the conductor 6|.

One terminal of the selenium cell I3 is connected by the conductors 14, H and 'l5 with one terminal of the electric magnet 65 and the other terminal of the selenium cell 13 is connected by the conductor I6 with the other terminal of the electric magnet 65. The terminals of the lamp 66 are in turn connected to a suitable source of electric energy 11 by the conductors I8 and 18 respectively. V 7

From the foregoing, it will of course appear that when the motor 55 has actuated the aerial l8 so that it will train its face at right angles to the source of the radio impulse, the voltage applied to the rectifier tubes 2| and 22 will be equal and the needle ll returned to its zero position where the light from the lamp 66 will be reflected back upon itself by the reflector 61 and none of the light rays directed onto the selenium cells 68 and I3 therebyin turn to deenergize the electric magnets 64 or 65 to release the movable contact 58' and interrupt the current of the motor 55.

The mechanism now to be described; will show how the angles a and b of Fig. 1A formed between lines extending at right angles to the loop aerials 8, I l and I2 from their respective sources of radio impulses may be translated into corresponding degrees of electrical energy.

For this purpose, there is fixed the shaft 88 to suspend from the support 36 on which in turn are journaled the three sprocket wheels 8|, 82 and 83, the sprocket wheel -8l being connected by the sprocket chain 84 with the sprocket wheel 48, sprocket wheel 82 by thesprocket chain 85 with the sprocket wheel 4| and sprocket wheel 83 by the sprocket chain 86 with the sprocket wheel 42.

The sprocket wheel 82 has an upwardly extending semi-annular resistance 81 to cooperate with the brush 88 extending down from the sprocket wheel 8|. The sprocket 82 also has a downwardly extending semi-annular resistance 88 to'cooperate with the contact 88 extending upthe conductor 8| with the source of electric current 82 and in turn by the'conductor 83 with one terminal of the meter 84.

"The brush 88 cooperating with the resistance 8] is in turn connected by the conductor 85 with the other terminal of the meter 84. One terminal of the resistance 88 is in turn connected by the conductor 86 with the source of electric current 91 which is in turn connected by the conductor 88 with one terminal of the'meter 88. The brush 88 cooperating with the resistance 88 is in turn conrected by the conductor I88 with the other terminal of the meter 88.

The sprockets 81, 82 and 83 are arranged on the shaft 88 in such a manner that in the present in- 82 which is parallel to the plane of the loop aerial 5 and the contact I04 is positioned in a line that II; and that the contact arm 90 is on a diameter of the sprocket 83 which is parallel to the plane of the loop aerial I2.

Thereupon the angle formed by the diameters --bearing the contact arm 88 and the terminal of the resistance 81 will be equal to the angle formed by' the planes of the loop aerials I0 and I I, and the amount of electrical-resistance in the resistance 81 included between the terminal of the resistance 81 and the contact 88 will be proportional to the whole amount of electrical resistance possible in the entire arc of one hundred and eighty degrees of the resistance 81' as the angle between the planes of the loop aerials I0 and II will be proportional to the one hundredand eighty degree are possible between said planes.

Furthermore, the angle formed by the diam- I cters bearing the contact arm 90 and the terminal of the resistance 09 will. be equal to the angle formedby the planes of the loop aerials I2 and I I, and the amount of electrical resistance in the resistance 89 included between the terminal of the resistance 89 and the contact 90 will be proportional to the 'whole amount of electrical resistance possible in the entire arc of one hundred and eighty degrees of the resistance 89 as the angle between the planes of the loop aerials II and I2 will be proportional to the one hundred ,and eighty degree are possible between said planes.

Given an arc of one hundred and eighty derees each for the resistances 81 and 89 and assuming that the resistances are so wound that successive areas correspond in resistance to corresponding increments of an one hundred and eightly degreemeter are, it will of course be obvious that the needles IOI and I02 will intercept arcs on the meters 94 and 99 to measure degrees corresponding to the angles a and b equal to the angles formed between the imaginary lines-drawn at right angles to the faces of the aerials I0, II and I2 from their respective sources of radio impulses corresponding to the angles a and b, see Fig. 1A.

The apparatus now to be described is used to translate the electrical energy of the meters 94 and 99 stepping on the angles a and b', Fig. 1A, corresponding to the positions of their needles "II and I02 into mechanical forces stepping ofi angles d and c, Fig. 1A, to determine the posltions of the contacts I03 and I04 relative to the resistance coils 'I82- and I85 respectively. Since 'the contact I03 is positioned ina line that is radial to the discs mounted to rotate about the axial center I3I corresponding to the station A is radial to the discs mounted to rotate about .the axial center I32 corresponding to the station C. it is of course obvious by reference to the diagram -oi? Fi 1A that the axial centers I3I and I32 may be assumed to correspond in position to the stations or sources of radio impulses A and C respectively and that the point of intersection of the lines drawn through contact m and center I3I' with the line drawn through contact I04 and center I32 will correspond to the point P' in the circle determined by the points A, C and the point corresponding to the unknown location point P,.where the line corre sponding to the line drawn ,from the aerial-II through the station 3 will intercept such circle,

. and that the arcs on the resistances I82 and I85 intercepted by the contacts I03 and I04 will correspond to the angles 0 and d.

To solve this part of the problem, it is there-' fore only necessary to determine the position of the rod corresponding to the line drawn through the station 13' and the point P. For this reason, initially it is only necessary to manually set an abutment or point I05 at a position to correspond to the position of the station B relative to the stations A and C.

This abutment I05 in the present instance is fixed to the rod I06 corresponding in position to the line drawn from the aerial II through the point P. The position of the pin I05 relative to the centers I3I and I32 will be determined by the angles formed by the lines connecting these several points on a map on which the positions relative to one another of the stations A, B and C are accurately determined.

The map I in the present instance shows a part of the eastern portion of the United States in which the cities of Cleveland, Washington and New York are located and for the purpose of the description, the location of Cleveland is desig-- nated as A station, the location of Washington as B station and the location of New York as C station.

On this map I a triangular apparatus IN is 35 manually set with the pins 2, 3 and 4 piercing the map at the stations A, B and C.

The triangular apparatus I0'I consists essentially of an arm I08 having an enlargement I09 at one end provided with an arcuate slot IIO which corresponds to slightly more than a'right angle and is calibrated in the present instance from twenty below zero to ninety above zero. Longitudinally of the arm I08, there is also provided a longitudinally extending slot III. In the present instance, the calibration zero alines with the slot III. In the enlargement I09 and in alinement with the axial center of the slot IIO, there is secured the pin 4. This pin 4 being fixed in alinement with the axial center of the slot IIO will of course'also be in alinement with the longitudinally extending slot III.

On the enlargement I09, there is mounted the meter 0 with its base II2 also in alinement with the center of the longitudinally extending slot III and its arcuate portion a needle 9 extending away from the axis I.

Preferably as shown in Fig. 12 an enlarged head II3 is mounted to extend above the meter 0 and substantially in alinement with the pin 4 to facilitate locating the pin 4 at the station desired.

In alinement with the pin 4, there is a pivot pin extending through the slot II4 of the arm II5, the slot II4 extending longitudinally of the is disposed below the enlargement I09 and has a pivot pin at its axis 1 to pivotally connect it to the arm II 6 having a longitudinally extending slot I" through which extends a pivot pin in alinement with the pivot pin 2. Extending through the slot II4 oi the arm I01 and the slot IIO of the enlargement I09 where the slots H4 arm II 5., This arm H5 in the present instance and H0 cross one another, there is provided the 1L 7 the longitudinally extending slot II1, there is provided the pin I which is slidably mounted in both slots. Extending upwardly from the scale II8 there is also provided a pin I2I fixed to the scale, II8 but slidable in the longitudinally extending slot III. The pivot pin in alinement with the pin 2 is slidably mounted not only in thelongitudinally extending slot II1 but also in the; longitudinally'extending slot III. The pin I20 in turn acts as an-indicator to register with the calibration on the scale II8 corresponding to the angle formed by the arms H6 and I08.

The meter 5 is fixedly secured to the scale II8 so that its base due to the pin I2I will be disposed in alinement with the center of the slot III and its arcuateportion and needle '8 will extend away from the axis 1.

Initially after the triangular apparatus I01 has been secured in place with the pins 2, 3 and 4 located at the-stations A, B and C, the angle in degrees formed at the points A and C will be read on the scales I09 and H8 and upper discs I22 and I23 manually rotated by the thumb screws I24 in alinement with the shafts I25 and. I26 until these two discs show a reading at windows I21 and I28 corresponding to the' reading on the scales H8 and I09 respectively whereupon the abutment I 05 will bepositioned relative to the centersof rotation I3I and I32 of the discs I 22 and I23 respectively to correspond to the position of the pins 2, 3 and 4 on the map I. In other words, the readings on the scales H8 and I09 of the triangular apparatus I01 are relied upon to positionthe abutment I05 corresponding to the station B relative to the centers of rotation I3I and I32 of the discs I 22 and I23 respectively and electrically controlled mechanical means still to be described are relied upon to position the discs I29 and I30 and thereby step of! portions of the resistances I82 and I85 corresponding to the angles 0 and d, see Fig. 1A and which portions of resistances are connected to the meters 6 and =6 to position the arms 9 and 8 respectively to form angles 0' and d respectively and intersect at a point corresponding to the unknown location point If .on the map I.

The apparatus contained in the housing I6 including the discs I22 and I23 which is used to convert the electrically controlled mechanical means for determining the angles 6 and d, see Fig lA, into electrical energy to position the arms 9 and 8 will now be described.

The housing I6 preferably consists of an upper section I33 and a lower section I34. The discs I22 and I23 are mounted in the upper section I33 and thev discs I29 and I30 are operatively associated with the lower section. The disc I22 is preferably pivotally connected to a stub shaft I35 extending downwardly from the cover I36 of the housing I6 on which shaft I35 there is also pivotally mounted the gear I31 in mesh with the spur gear I38 on the shaft, I25 of the control abutment I24.

The disc I23 mounted to rotate about a diflerent axisthan that of the disc I22 is pivotally connected to the pin I39 about which is pivotally mounted the center of the. gear I40 which meshes with the spur gear MI and is maintained in alinement about its center of rotation by the three guide rollers I42, I43 and I44, the guide roller I42 being rotatably mounted upon the extension I and the guide rollers I43 and guide rollers I42, I43 and I44 engaging the outer periphery of the gear I40.

The cover I 36 is provided with two windows I21 and I28 preferably at opposite sides of the'housing I6 to register with the graduated portions I46 and I41 respectively of the discs I22 and I23 so that when the thumb screws I24 are manipulated to turn the spur gears I38 and I 4|, they will in turn actuate the gears I31 and I40 by the connection now to-be described, in turn to indicate at the windows I21 and I28, the respective angles formed between the centers of rotation I3I and I32 and the pin I05.

The discs I22 and I23 have formed therein the straight slots I48 and I49 respectively through which extends the upper end ofthe pin I05 where the slots I48 and I49 cross one another, the slots being of course cut relative to one another and to the graduations I46 and I41 so that the angles formed between the lines drawn between the centers of rotation I3I and I32 and the pin I05 at the centers of rotation I 3| and I 32 will correspond to the degree noted at the windows I21 and I28.

The disc portions of the gears I31 and I40 in turn are provided with spiral shaped slots I50 and I5t respectively with their overlapping points or portions in alinement with the overlapping Points of the slots I48 and I49 so as to receive the pin I05, the formation of the slots I50 and I5I being provided in order to reduce the friction to a minimum, the force being applied to the gears I31 and I40 in which the latter slots are contained.

In view of the foregoing it will then appear that when the spur gear I38 is turned in a clockwise direction the gear I31 will be turned oppositely around its center I3I and the radial distance from that center to the pin I05 in the curved slot I50 in the disc I31 will become less and less as the gear '138 is turned more and more. It will also be seen that as the pin I05 moves toward the center I3I it must slide in the straight slot I48 in the disc I22 which will turn the disc I23 in turn to cause the angle formed at the center I32 by the slot I49 with an imaginary line between the centers I3I and I32 to come smaller and be indicated by a reading in degrees through the window I28. Similarly when the spur gear I38 is turned in a counter clockwise direction, the radial distance from the center I3I to the pin I05 in the curved slot I50 will become greater and the pin I05 will slide in the straight slot I46 outwardly from the center I3I and turn the disc I23 in turn to cause the angle formed at the center I32 by the slot I49 with an imaginary line between the centers I3I and I 32 to become-larger and be indicated by a reading \in degrees through'the gears applies when the spur gear MI is turned.

It can easily be seen that a clockwise turning of gear I4I causes the angle reading through the window I21 to become greater while a counter clockwise turning causes the angle reading to be less.

The pin I05 has pivotally connected to it the rod I06 which is restricted to slide between two pairs of fingers, the pair I52 and I53 and the pair I54 and I55 extending upwardly at opposite ends of the annulus I56 to maintain the rod or bar I06 extending diametrically across the center of rotation of the annulus I56.

The annulus I56, see Figs. 5, 9 and 10, has two resistance windings, each covering one half of the annulus, separated by the bar I06, and is 5 alinement with the slots I18 in turn mounted upon the arm I51 extending outwardly from the hub I58 rotatably on the upper end of a shaft I59 which constitutes the pin which extends through four discs, to wit the discs I29 and I30 and their associated discs I60 and I6I respectively, the disc I60 being mounted to rotate relative to a common pivot pin I62 at the center of rotation of the disc I29, whichcenter of rotation in turn alines with the center of rotationI3I of the disc I22, and the disc I6 I being mounted to rotate about a common pivot pin I63 at the center ofrotation of the disc I30, which center of rotation in turnalines with the center of rotation I32 of the i5 disc I23.

The discs I29 and I60 are maintained in axial alinement with the disc I22 by the three guide rollers I64; I65 and I66 which engage the periphery of the disc I60, the guide roller I64 being journaled in the extension I61 extending downwardly from the section I33, the roller I65 being ,iournaled in the end of one arm I68 of the bracket I69 and the roller I66 being journaled in the end of one arm I10 of the bracket III.

The discs I and I6I are in turn maintained 'in axial alinement with the disc I23 by the three guide rollers I12, I13 and I14 which engage the periphery of the disc I6I, the guide roller I12 being journaled in the extension I15 extend- 30 ing inwardly from the section I34, the roller I13 being journaled in the end of the arm I16 oi the bracket I69 and the rollerI14 being 'journaled in the end of the arm I11 of the bracket I1 I.

The discs I29 and I30 have-straight slots I18 and I19 respectively which crossione another to receive the shaft I59 at their overlapping portions, and the discs I60 and I6I have spiral slots I80 and I8I respectively which cross one another at a point in alinement with the point where the slots I18 and I19 overlap, also to receive the shaft I59 whereby the discs I29, I 60, I30 and I6I may constantly bear predetermined relations to one another and as a result of which the actuation of the discs I60 and I6I 5 will determine the position of the discs I29 and 55, diallyfrom the sliding block I84, in alinement with the slot I 18 in the disc I29 but rotatably mounted on the shaft I59, and the contact I04 is maintained in engagemeht'with the resistance winding I85, being formed at the end of a spring i0 arm I86 extending radially from the upper end of the shaft I59.

The sliding block I84 has plane faces engaging the faces of the slot I18 whereby the contact I03 when once arranged to aline with theslot $5 I18 will be maintained to aline with the same throughout the movement of the shaft I59 relative to the slot I 18. In turn the sliding block I 81 has plane faces engaging the lateral faces 'of the slot I19 whereby the contact I04 when '0 once alined with the slot I19 will remain so alined throughout the movement of the shaft I59 relative to the slot I19.

The positions of the discs I29 and I80 relative to one another will depend upon and be in 8 alinementwith, the positions of the needles I02 aooaooe Q and IM respectively which control the actuation of the electric motors I88 and I89 respectively mounted on the platform I90 of the housing I6.

The motor I88 is provided with a shaft I9I to which is fixed the beveled gear I92 in mesh with the beveled gear I93 fixedto the shaft I94 journaled in the bearing I95 and having at its upper end a spur gear I96 in mesh with the toothed extension I91 secured to the lower outer edge of the disc I60. The lower end of the shaft I94 in turn has fixed to itthe gear I98 in mesh with the toothed periphery of the gear I99 of the same diameter as the discs I29 and I60 mounted on the shaft 200 journaled in the lower face of the platform I90, on which shaft 200 is mounted the light sensitive housing 20I, see Fig. 7,

6,- to rotate over and *about the meter 99 supported on the base 203 of the housing I6.

The housng 20I preferably has an outer contact ring 2 4 for the brush 206 which is con- The shaft 2I6 of the meter 98 may or may not be provided with the needle I02 but is preferably provided with a reflector 2I1 positioned at zero position to reflect the light rays from the lamp 2I8 back upon the lamp '2I8 mounted to direct light rays through the aperture 2I9 formed between the inner ring portions 2 and 2I4.

The inner ring portions 2 and 2I4 are preferably electrically separated from one-another and connected with the innermost layers 220 and HI of the housing 20I constituting layers of wire mesh which arespaced from the contact 222 by the two sections 223 and 224 of a light sensitive substance such as the salt used in selenium cells or the like.

The motor I 88 is reversible having a common conductor 225 connected to one terminal ofthe source of electric current 226, the other terminal of which source 226 is connected by the conductor 221 with the movable contact bar 228 normally maintained spaced from the magnets 201 and 209 in zero position of the needle I02 as shown in'Fig. 1.

One of the windings for actuating the motor in one direction is connected by the conductor by the movable contact 228 when the electromagnet 201 is energized and the other winding for turning the motor I88 in the other direction is connected by the conductor 23I to the fixed contact 282 to be engaged by the movable contact 228 when theelectromagnet 209 is energized. o

The motor I39 is provided with a shaft 235 to which is fixed the beveled gear 236 in mesh with the beveled gear 231 fixed to the shaft 238 journaled in a bearing, not shown, mounted on the platform I90 and which shaft 235 has at its upper end the spur gear 288 in mesh with the toothed extension 240, secured tothe lower outer edge of the disc i6'I.

0n the platform I90, there is mounted the meter 94 and cooperating with it, there is pro vided the light sensitive device 2 secured to the shaft 242 co-axial with the center of rotation of the disc IGI.

The light sensitive device 24I is constructed similar to the light sensitive device 20I and therefore like reference characters will be applied to indicate like parts without further describing the same and since the light sensitive device 24I also cooperates with the meter 94 in the same manner that the device 20I cooperates with the meter 99 to control the motor I89, the wiring between the motor I89 and its electromagnets 243 and 244 will not be described in detail except to state that energization of the electromagnet 243 by the light sensitive device 24l will effect actuation of the motor I89 in' one direction and that energization terminal connected by the conductor 246 to one terminal of the source245 and the other terminal connected by the terminal 241 to the other terminal of the source 245.

From the foregoing, it will thus appear that I the angles a and b, Fig. 1A, stepped off by the aerials" I0, II and I2, after the pin I05 has been manually set will in turn be converted into angles d and c and so be steppedoff on the annulus I56, see the circle 8, Fig. 1A.

J It is now only necessary to set the meters 5 and '6 to measure angles so stepped off, with the needles 8 and 9 operating about the centers A and C of the map I to cross one another to determine the unknown location point P. This is eife'cted by connecting the resistances stepped off by the contacts I03 and; I04 with the meters 5 and 6 through their respective sources of current. To do this the contact I04 is connected by the conductor 248 with one terminal of the source of electric energy 249 and the other terminal of the source 249 connected by'the conductor 250 with one terminal of the meter 5 and theother terminal of the meter 5 connected by the conductor 25I with one terminal of the winding l82,and the contact I03 is connected by the conductor 252 with one terminal of the source of electric energy 253 and the other terminal of the .source 253 connected'by the conductor 2.54 with one terminal of the meter 6 and the other terminal of the meter .6 connected by the conductor 255 with one terminal of the winding I85.

It is of course obvious that the various sources of electric energy referred to may all be the same, in other words that one 'common source of electric energ may supply all of the several working parts with the possible exception of the light sensitive devices without departing from the general spirit of the invention, the sources having been illustrated separately in the interest of cleamess. L

It is ,obvious that various changes and modifications may be made to the details of construction without departing from the general spirit of theinventionas 'set forth in the appended claims.

I claim:

1. A location finder including'a chart of a predetermined portion of the earths surface, a support associated with said chart, two indicating sources of radio impulses, electric rotors operaarms pivotally mounted on said support with centers of rotation registering with locations on said chart corresponding to two of three known fixed tively connected to said arms, and means tuned to receive the radio impulses of said three known fixed sources of radio impulses and operatively connected to said electric rotors to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location.

2. A location finder including a chart of a predetermined portion of the earth's surface, a support associated with said chart, two electric meters mounted on said support with rotatable shafts registering with locations on said chart corresponding to two of three known fixed sources of radio impulses, an indicating arm secured to each of said shafts, and means tuned to receive the radio impulses of said three known fixed sources 'of radio impulses and operatively connected to said electric meters to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location.

3. A location finder including a chart of a predetermined portion of the earth's surface, a support associated with said chart, two electric meters mounted on said support with rotatable shafts registering with locations on said chart corresponding to sourcesof radio impulses, an indicating arm secured to each of said'shafts, three loop aerials, means for training said loop aerials at right angles to their respective sources of radio impulses located at three known locations relative to said chart, means for electrically measuring the angles formed between lines drawn at right angles to said loop aerials, electric circuits including resistances, movable contacts and said meters for electrically stepping ofic' angles corresponding to the angles formed by lines drawn from two of said aerials to their respective sources of radio impulses and a line connecting said sources of radio impulses to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location, and mechanical means operatively associated with said electrical measuring means and tosaid movable contacts to position said movable contacts according to the angles measured by said electrical measuring means.

4. A location fin er including a chart of a predetermined portion of the earth's surface, a support associated with said 'chart, two electric meters mounted on said support withrotatable shafts registering with locations'on said chart corresponding to two known sources of radio impulses, an indicating arm secured to each of said shafts, two loop aerials, means for training said two loop aerials at right angles to the .two sources of radio impulses corresponding to the locations of said meters on said chart, a third loop aerial, means for training said third loop I aerial at right angle to a third known source of radio impulses, means for electrically measuring the angles formed between lines drawn at right angles to said loop aerials, electric circuits including resistances, movable contacts and said meters for electrically stepping off angles corresponding to the angles formed by lines drawn from saidtwo first mentioned loop aerials 'to their respective sources of radio impulses and a line connecting said latter sources of radio impulses to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location, and mechanical means operatively associated with said electrical measuring means and to said movable contacts to position said movable contacts according to the angles measured by saidelectrical measuring means.

,locations of said meters on said chart, a third loop aerial, means for training said third' loop aerialat right. angles to a third known source of radio impulses, means for electrically measuring the angles formed between lines drawn at rightangles tosaidloop aerials including an annulus having two resistance windings operatively associated with one of said loop aerials, movable contacts operatively associated with said other two loop aerials, each engaging one of said resistance windings and means responsive to said resistances operatively connected to actuate said meters in turn to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location. 6. A location finder including a chart of a predetermined portion of the earths surface, a support associated with said chart, two electric meters mounted on said support with rotatable shafts registering with locations on said chart corresponding'to two known sources of radio impulses, an indicating arm secured to each of said shafts, two loop aerials, means for training said twov loop aerialsat. right angles to the two sources of radio impulses corresponding to the locations of said meters on said chart, a third loop aerial, means for training said third loop aerial at right angles to a third known source of radio impulses, means for electrically measuring the angles formed between lines drawn at right angles to said loop aerials, electriccircuits including resistances, movable contacts and said imeters for electrically stepping ofi angles correpulses to actuate said arms to cross one another in registrationwith a point on said chart indicating the unknown location, and mechanical means operatively associated with said electrical measuring means and .to said movable contacts to position said movable contacts according to the angles measured by said electrical measuring means, saidmeans for training said loop aerials at-right angles to their respective radio impulses including light sensitive devices responsive'to deflections of said loop aerials from positions at right angles to their respective sources of radio impulses to actuate and maintain said loop aerials at right angles to their respective sources of radio impulses.

'7. A location finder including a chart of a'predetermined portion of the earth's surface, a support associated with said chart, two electric meters mounted on said support with rotatable shafts registering with locations on said chart corresponding to two known sources of radio impulses, an indicating arm secured to each of said shafts, two loop'aerials, means for training said two loop aerials at right angles to the two sources of radia impulses corresponding to the locations of said meters on said chart, a third loop aerial,

means for training said third loop aerial at right angles to a third known source of radio impulses,

means for electrically measuring the angles formed between lines drawn at right angles to said loop aerials, two discs having difierentcenters of rotation corresponding to the positions of said first two known sources of radio impulses, there being slots in said discs,- a pin extending through both of said slots, means for actuating said discs in'turn to position said pin to form a triangle with said two centers of rotation corresponding to the triangle formed by said three known sources of radio impulses on said chart, a guide bar connected to said pin, and electric circuits including resistances, movable contacts and said meters for electrically stepping off angles corresponding to the angles formed by lines drawn from said two first mentioned loop aerials to their respective sources of radio impulses and a line conmeeting said latter sources of radio impulses to actuate said arms tocross one another in registration with a point on said chart indicating the unknown location, said guide bar being connected to said resistances to determine their positions relative to said centers of rotation, and-mechanical means operatively associated with said electrical measuring means and to said movable contacts to position said movable contacts relative'to said centers of rotation and to said resistances to correspond to the angles measured by said electrical measuring means.

8. A location finder including a chart of a predetermined portion of the earth's surface, a support associated with said chart, two electric meters mounted on said support with rotatable shafts registering with locations on said chart corresponding to two lmown sources of radio impulses, an indicating arm secured to each of ,said

shafts, two .loop aerials, means for training said two loop aerials at right angles to the two sources of radio impulses corresponding to the locations of said meters on said chart, a third loop aerial," means for training said'third loop aerial at right angles to a third known source of radio impulses, means for electrically measuring the angles formed between lines drawn at right angles to said loop aerials, electric circuits including resistances, movable contacts and said meters for electrically stepping ofi angles corresponding to the angles formed by lines drawn from said two first mentioned loop aerials to their respective sources of radio impulses and a line connecting said latter sources of radio impulses to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location, two discs having different centers of rotation corresponding to the positions of said first two known sources of radio impulses, there being slots in said discs, a, pin extending through both of said slots and the center of rotation of said resistances, means operatively connected to said electrical measuring means for actuating said discs in turn to position said pin to form the apex of a triangle, whose base will form inside angles with its sides equal to the angles formed between lines drawn from said loop aerials to their respective sources of radio impulses in turn to position said contacts on said resistances to step off angles corresponding to the angles formed between lines drawn from the two first mentioned loop aerials to their respective sources of radio impulses and a line connecting said latter sources of radio impulses.

9. A location finder including a chart of a predetermined portion of the earth's surface, a support associated with said chart, two indicating arms pivotally mounted on said support with centers of rotation registering with locations on said chart corresponding to two of three known sources of radio impulses, electric rotors operatively connected to said arms, and means including loop aerials tuned to receive the radio impulses of said three known sources of radio impulses and operatively connected to said electric rotors to actuate saidarms to cross one another in registration with a point on said chart indicating the unknown location, said latter I means being responsive to deflections of said loop aerials from positions at right angles to their respective sources of radio impulses to actuate and maintain said loop aerials at right angles to their respective sources of radio impulses.

10. A location finder including a chart of a predetermined portion of the earths surface, a support associated with said chart, two indicating arms pivotally mounted on said support with centers of rotation registering with locations on said chart corresponding to two of three known sources of radio impulses, electric rotors operatively connected to said arms, and means including loop aerials tuned to receive the radio impulses of said three known sources of radio impulses and operatively connected to said electric rotors to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location, said latp ter means including light sensitive devices responsive to deflections of said loop aerials from positions at right angles to their respective sources of radio impulses to actuate and maintain said loop aerials at right angles to their respective sources of radio impulses.

11. A location finder including a chart of a predetermined portion of the earths surface, a triangular device having three arms pivotally connected to oneanother, pins in alinement with the pivotal connecting points of said three arms to pierce said chart at points corresponding to three predetermined sources of radio impulses and thereby anchor said triangular device to said chart, an electric meter mounted at each of two of said pivot points with its center of rotation in alinement with such pivot point,

each meter having an indicating arm extending from its center of rotation to cross the arm of the other meter at some point on said chart, and means tuned to receive the radio impulses of said sources of radio impulses and operatively connected to said electric meters to actuate said means to cross one another in registration with a point on said chart indicating the unknown location.

12. A location finder including a chart of a predetermined portion of the earths surface, a support having two pins, each pin piercing said chart at a point corresponding to two of a greater number of known sources of radio impulses and thereby anchor said support to said chart, .two electric meters secured to said support each positioned with its center of rotation in alinement with one of said pins, each meter having an indicating arm movable about its center of rotation and movable to cross the other indicating arm at some point on said chart, and means tuned to receive the radio impulses of more than two known sources of radio impulses including the aforesaid two known sources and operatively connected to said electric meters to actuate said arms to cross one another in regthe unknown location.

13. A location finder including a chart of a predetermined portion of the earths surface, a support associated with said chart, two indicating arms pivotally mounted on said support with centers of rotation registering with locations on said chart corresponding to two of three known sources of radio impulses, actuators op eratively connected to said arms, and means tuned to receive the radio impulses of said three known sources of radio impulses and operatively connected to said actuators to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location.

14. A location finder including a chart of a predetermined portion of the earths surface, a support associated with said chart, actuators mounted on said support with rotatable shafts registering with locations on said chart corresponding to two of three known sources of radio impulses, an indicating arm secured to each of said shafts, and means tuned to receive the radio impulses of said three known sources of radio impulses and operatively connected to said actuators to actuate said arms to cross one an-- other in registration with a point on said chart indicating the unknown location.

15. A location finder including a chart of a predetermined portion of the earths surface, a support associated with said chart, two electric meters mounted on said support with rotatable shafts registering with locations on said chart corresponding to two known sources of radio impulses, an indicating arm secured to each of said shafts, two loop aerials, means for training said two loop aerials at right angles to the two sources of radio impulses corresponding to the locations of said meters on said chart, a third loop aerial, means for training said third loop aerial at right angles to a third known source of radio impulses, means for electrically measuring the angles formed between lines drawn at right angles to said loop aerials, two pairs of discs, the discs of 'each pair having a common center of rotation but differing from the center of rotation of the other pair, there being a straight slot in one disc of each pair, there being a spiral slot in the other disc of each pair, a pin extending through both sets of slots, means for actuating said discs in turn to position said pin to form a triangle with said two centers of rotation corresponding to the triangle formed by said three known sources of radio impulses on said chart, a guide bar connected to said pin, and electric circuits including resistances, movable contacts and said meters for electrically stepping off angles corresponding to the angles formed by lines drawn from said two first mentioned loop aerials to their respective sources of radio impulses and a line connecting said latter sources of radio impulses to actuate said arms to cross one another in registration with a point on said chart indicating the unknown location, said guide bar being connected to said resistances to determine their positions relative to said centers of rotation, and mechanical means operatively associated with said electrical measuring means and to said movable contacts to position said mpvable contacts relative to said centers of rotatip'fi and to said resistances to correspond to the angles measured by said electrical measuring means.

16. A location finder including a chart of a predetermined portion of the earthssurface, a support associated with said chart, two electric meters mounted on said support with rotatable shafts registering with locations on said chart corresponding to two known courses of radio impulses, an indicating arm secured to each of said shafts, two loop aerials, means for training said two loops aerials at right angles to the two sources of radio impulses corresponding to the locations of said meters on said chart, a third loop aerial, means for training said third loop aerial at right angles to a third known source of radio impulses, means for electrically measuring the angles, formed between lines drawn at right angles to said loop aerials, electric circuits including resistances, movable contacts and said meters for electrically'stepping off angles corresponding to the angles formed by lines drawn from said two first mentioned loop aerials to their respective sources of radio impulses and a line connecting said latter sources of radio impulses to actuate said arms to cross one another in registration with a point on said chart'indicating the unknown location, two pairs of discs, the

discs of each pair having a common center ot rotation but diflering from the center of rotation I of the other pair, there being a straight slot in one disc of each pair, there being a spiral slot in the other disc of said pair, a pin extending through both 'sets of slots and the center of rotation of said resistances, means operatively connected to said electrical measuring means for actuating said discs in turn to position said pin to form the apex of a. triangle, whose base will form inside angles with its, sides equal to theangles formed between lines drawn from said loop aerials to their respective sources of radio impulses in turn to position said contacts on said resistances to step 05 angles corresponding to theangles formed between lines drawn from the two first mentioned loop aerials to their respective sources of radio impulses and a line connectlng said latter sources of radio impulses.

OSCAR A. BOOK. 

